Exemplary embodiments of the present invention relate to a brake disc having a pot and a friction ring. In addition, the invention relates to a pot and a friction ring for such a brake disc, as well as a method for the production of such a brake disc.
A brake disc is typically a component of a braking assembly for braking a vehicle wheel, in particular of a motor vehicle. The brake disc comprises a friction ring and a pot, wherein the pot is arranged concentrically in an opening of the friction ring. The connection between a hub of a wheel carrier of a wheel suspension and the brake disc is carried out by means of the pot, while the braking process is typically carried out by means of brake shoes of the braking assembly that interact with the friction ring. To transfer the respective torsional moment, the pot and the friction ring engage with each other via a gearing system, for example. An axial securing of the friction ring on the pot is also necessary to secure the brake disc against axial displacements of the pot relative to the friction ring, which can be caused by lateral forces acting on the vehicle.
German patent document DE 44 19 757 discloses a brake disc having radial stampings on the pot, which support the pot against the friction ring and thus secure it axially. It is hereby disadvantageous for an increased radial space requirement to arise. In addition, this brake disc requires increased cooling complexity.
Another brake disc is known from German patent document DE 20 13 535, which has projections along an edge of the pot, the projections engaging with slots in the friction ring. However, the slots reduce the transferability of the torsional moment between the pot and the friction ring.
A further brake disc is known from German patent document DE 26 41 443, where the pot has longitudinal grooves, with which the friction ring engages in order to guarantee the radial securing. However, the friction ring and the pot remain axially displaceable. Furthermore, this brake disc, as a result of the longitudinal grooves, has a low thermal flexibility of the friction ring and the pot, in particular during thermal expansion.
Further brake discs are known from German patent documents DE 44 20 758 and DE 198 30 669, wherein the pot and the friction ring each have a gearing system that engages with the other in order to guarantee radial securing, while projections or stampings of the friction ring and/or the pot guarantee axial securing.
The present invention is directed to an improved, or at least alternative, embodiment for a brake disc having improved axial security and a high level of transferability of a torsional moment between the friction ring and the pot of the brake disc.
In accordance with exemplary embodiments of the present invention at least one pot tooth space of a pot of a brake disc is equipped with a flap radially overlapping a corresponding annular tooth of a friction ring of the brake disc on at least one axial end. The annular tooth is a component of an annular gearing system running along an inner periphery of the friction ring, which has an opening. The pot has a floor and a wall that encloses it and protrudes from it, into which wall the opening is introduced in such a way that the pot and the friction ring have a concentric arrangement. The pot tooth space is a component of a pot gearing system running along an outer periphery of the wall and has pot teeth that are each separated from one another by such a pot tooth space. The pot gearing system and the annular gearing system run annularly in a closed manner. Its teeth hereby extend in the axial direction, wherein the axial direction relates to a rotational direction of the brake disc and thus to the axial direction of the brake disc. Accordingly, the radial direction relates to the direction running perpendicular to the axial direction. The pot gearing system is formed by the pot teeth, which protrude radially outwards, and the pot tooth spaces, while the annular gearing system is formed by the annular teeth that protrude radially inwards and are separated from one another by respective annular tooth gaps. The pot gearing system and the annular gearing system are, in addition, designed to complement each other, such that the pot teeth engage with the annular tooth gaps and the annular teeth engage with the annular tooth gaps radially. Anti-rotation between the pot and the friction ring is hereby guaranteed, with which a torsional moment between the pot and the friction ring can be transferred.
According to exemplary embodiments of the present invention, the pot or the pot gearing system has at least one first pot tooth space on which the flap is molded. The flap protrudes radially outwards and can be in contact with the annular tooth that engages with the corresponding pot tooth space. In order to guarantee an axial securing of the pot relative to the friction ring, the flap ends radially overlap the corresponding annular tooth at its axial end. An axial end is the axial end of the respective annular tooth that faces the pot floor or faces away from the pot floor. An embodiment is preferred in which the flap overlaps the corresponding annular tooth on a first axial end. Due to axial securing that is guaranteed in this way, additional stampings and recesses in or on the pot or friction ring can be dispensed with. This has the consequence that the brake disc requires a reduced amount of space, in particular in the radial direction, to guarantee the axial securing and that the expansion of the brake disc in the radial direction can be reduced. In addition, the brake disc enables simplified cooling as a result of the space-saving design.
The flap that protrudes radially outwards is, for example, curved radially outwards. The curvature is preferably designed in such a way or a radius of curvature of the flap is selected in such a way that the flap does not exceed an external diameter or a perimeter of the pot or the wall. In addition, the flap and the corresponding first pot tooth space are preferably designed in such a way that the radius of curvature of the flap is greater than 2.5 mm. The flap can in particular be formed in a W shape from an axial perspective by the radial curvature.
An embodiment is preferred in which the pot gearing system has a closed shape and runs along the entire peripheral direction of the outer periphery of the wall. The complementarily designed annular gearing system also advantageously has a closed shape and runs along the entire peripheral direction of the inner periphery of the friction ring.
In a preferred embodiment, the annular tooth, which is radially overlapped by the flap, has an axial recess on its end that is overlapped by the flap, i.e. preferably on its first axial end. The flap is, in addition, formed or shaped in such a way that it engages with this recess axially. Due to the axial engagement of the flap with the axial recess of the corresponding annular tooth, a positive axial securing of the friction ring with respect to the pot is guaranteed. Embodiments are also conceivable in which the pot tooth has such axial recesses on both axial ends. As a consequence, two flaps can then be provided, which overlap both axial ends radially and engage axially with the respective recess. However, an embodiment is preferred in which this is only carried out on the first axial end. In addition, all annular teeth can have such an axial recess on this axial end, such that, during assembly, no attention has to be paid to the allocation of the annular teeth with respect to pot tooth spaces with flaps, provided that all annular teeth are designed to be the same.
According to a further preferred embodiment, the pot gearing system has at least one second pot tooth space, on which a projection is formed. The projection of the second pot tooth space protrudes radially outwards and overlaps the annular tooth, which engages with this pot tooth space, on one of its axial ends. The projection is arranged accordingly on this axial end of the second pot tooth space. Here, an embodiment is preferred in which the flap overlaps the corresponding annular tooth on the first axial end, while the projection overlaps the corresponding annular tooth on the second axial end. This means, for example, that, whereas the flap radially overlaps the corresponding annular tooth on its axial end facing the floor of the pot and, if necessary, engages axially with the axial recess, the projection overlaps the annular tooth, with which the corresponding second pot tooth space engages, on the axial end facing away from the floor. The flap thus guarantees the axial securing into an axial direction, while the projection guarantees the axial securing into the other, opposite axial direction. In addition, the projection is preferably designed in such a way that its radial expansion does not exceed the perimeter of the pot or the wall.
Here, an embodiment is preferred in which the first pot tooth space, with corresponding flaps, and second pot tooth spaces, with corresponding projections, are arranged in an alternating manner along the peripheral direction between respectively adjacent pot teeth. Thus, a consistent securing in both axial directions is particularly guaranteed. In addition, the first pot tooth spaces, as well as the flaps, and the second pot tooth spaces enable improved thermal flexibility of the pot and the friction ring. This means that an improved adaptation is provided, in particular during thermal expansion of the pot and/or the friction ring.
In an advantageous development of the solution according to the invention, the wall has a conical shape. The wall has, for example, a smaller external diameter on the end facing the pot floor than on the end facing away from the pot floor. Alternatively or additionally, the wall is designed in such a way that it has an axial section with a conical shape. A wall designed in this manner leads to an additional axial security, with which a tendency for displacement of the friction ring relative to the pot in the corresponding axial direction is prevented or at least reduced.
It should be noted that a pot for a brake disc according to the invention, which has at least one pot tooth space with a projection and/or at least one pot tooth space with a flap that has been cut free, which has not yet been molded, i.e. has not been radially deformed, also belongs as such to the scope of this invention.
It should furthermore be noted that a friction ring for a brake disc according to the invention, which has at least one annular tooth that has the axial recess on at least one first end, preferably on its first axial end, also belongs as such to the scope of this invention.
The brake disc can now be produced according to an advantageous use of the friction ring or the pot in accordance with the method described below.
Firstly, the pot is introduced into the opening of the friction ring in such a way that a respective annular tooth and a pot tooth space, as well as an annular tooth and an annular tooth gap, engage with one another. Thus, the concentric arrangement of the pot and the friction ring is also provided. Then the respective flap of the first pot tooth space is radially deformed outwards until the respective flap radially overlaps the respective annular tooth on the respective axial end and thereby secures it in the respective pot tooth space. Embodiments are also conceivable in which the flap is already formed before the mentioned deformation in the corresponding pot tooth space, e.g. by cutting free a section of the pot tooth space that forms the flap. The radial deformation preferably takes place by caulking, such that a reinforced connection between the pot and the friction ring is particularly provided.
According to a preferred embodiment, the respective flap is then axially deformed or pressed into the recess of the annular tooth, at the region that radially overlaps the respective axial end of the corresponding annular tooth, the recess being molded on the corresponding axial end of the annular tooth. Thus, a positive axial securing is provided.
Here, embodiments are preferred in which the respective deformation of the flap, which is caused by caulking and/or imprinting, takes place in a plastic/elastic manner. The deformation of this type in particular guarantees increased resilience of the brake disc.
The caulking of the flap in the respective method steps can take place in a force-controlled and/or route-controlled manner. The deformation thus takes place until a pre-determined shape of the flap has been achieved and/or until a pre-determined force is expended.
In the course of the method, the projections of the second pot tooth spaces can additionally be exposed. The exposure of the projections can thus take place in a separate, in particular preceding, method step, or run at the same time as one of the other method steps that has already been mentioned.
Further important features and advantages of the invention arise from the sub-claims, the figures and the corresponding description of the figures, using the drawings.
It is understood that the features that are cited above and are still to be illustrated below can not only be used in the respectively specified combination, but also in other combinations or individually, without exceeding the scope of the present invention.